In a statement on Thursday, E.On said it was aiming to "streamline its sales operations, in response to the changing way customers want to interact with their energy company when buying electricity and gas".

The 450 job losses would be in sales and sales support roles across the UK.

The company employs just under 12,000 staff in the UK, with about 6,000 of those dealing directly with customers, mainly through call centres based in Nottingham, Bolton and Leicester.

Mr Cocker said: “This is not a move we have taken lightly and we are fully aware this will be a difficult time for our colleagues potentially impacted by these changes. We can assure everyone affected that we will be providing as much support as we can.

“Our industry is changing and we need to look at how we deliver the best possible experience to our customers in the most effective and efficient way.

"It’s become increasingly clear that many of our customers want to contact us either online or over the phone, when seeking a new energy supplier. We need to respond to what our customers want and where we can we will."

E.On is the last ongoing mis-selling investigation. Four other suppliers - SSE, ScottishPower, EDF Energy and npower - have all paid millions of pounds in fines or compensation after Ofgem found they had breached rules.